Lawyers for the alleged Colorado theater gunman declined Wednesday to make their case at a preliminary hearing, setting the stage for a ruling on whether he can stand trial over the massacre.
The surprise decision came as more evidence was presented, including iPhone pictures taken by alleged killer James Holmes hours before the shooting last July, showing him posing with weapons, orange hair and black contact lenses, AFP reported.
Judge William Sylvester adjourned the court after the defense announcement, scheduling a new hearing for Friday for Holmes' possible arraignment, if the judge decides to call a trial as appears increasingly likely.
Holmes, 25, is accused of killing 12 people and injuring at least 58 in the shooting in a midnight premiere screening of the latest Batman movie in a theater in Aurora, Colorado.
Since Monday prosecutors have called witnesses who gave harrowing accounts of the slaughter, and played 911 emergency calls in which the chaos and loud gunshot booms could be clearly heard.
Holmes' lawyers were expected to present witnesses Wednesday to bolster a case that he may be mentally unfit to stand trial. But in the end they announced they would not.
"We've had a change of position," public defender Daniel King told the court in Centennial, Colorado, where Holmes has sat staring vacantly as he listened to the chilling evidence against him.
"This is neither the proper venue or time to present a show or some truncated defense. This is not a trial. We have no evidence or argument about probable cause," King added.
Before the defense decision, prosecutors finished questioning a last witness, who gave testimony including about photos taken from Holmes' iPhone hours before the slaughter on July 20 last year.
One showed him posing with a Glock handgun, with his reddish orange hair -- subsequently seen in his first appearance in court after the massacre -- and black contact lenses, which were later found in his apartment.
Another of the pictures, presented in court, showed a bed with items later recovered from the theater and his apartment, including a bullet-proof vest and gun magazines.
Prosecutor Karen Pearson said the pictures added to evidence that Holmes had planned the theater massacre in detail in advance, and that the killings therefore amount to premeditated murder.
Other pictures recovered showed that Holmes had checked out the theater well in advance, both from inside and in the rear parking lot near the emergency exit he came in through before opening fire.
"He picked the perfect venue for this crime," Pearson said. "He didn't care who he killed. He intended to kill them all. He certainly had enough ammunition to do so."
"The pictures go to deliberation, motive and intent," she told the court, adding that earlier evidence about Holmes' purchase of weapons, ammunition and body armor also showed meticulous planning.
Before this week's hearings there had been speculation that Holmes' lawyers could seek a plea agreement, under which he would admit guilt in return for, for example, avoiding the death penalty.
His lawyers could also have argued that he was mentally unfit to stand trial, though that appears unlikely given their decision not to present witnesses after all.
The judge adjourned the case until Friday morning at 9:00 am (1600 GMT), when Holmes could be arraigned for trial. His decision could be announced before that online, court officials said.